user icons

[Ralph Döring]

Hi,

refer to section 3.3 "Toolbar" in the manual Customization.lyx:
"... If you draw some nice icons, you can submit them to the LyX team,
and we'll
 provide support for them in a future release."

It would be nice, if someone could tell me how to create such icons
(which format) and the way to insert it to LyX.
Thanks in advance.

--
  Ralph Döring